The present invention relates to a liquid crystal display device including color filters and switching elements such as TFTs (Thin-Film Transistors) which are formed on a common substrate, and a manufacturing method of the liquid crystal display device.
FIG. 1 is a schematic plan view showing a channel-etched type TFT which is formed on an active matrix substrate of a conventional liquid crystal display device, in which the layout of a pixel is a shown. FIG. 2 is a cross sectional view of the TFT of FIG. 1. FIGS. 3A and 3B are cross sectional views of pads of the TFT of FIGS. 1 and 2, in which FIG. 3A shows a gate pad section and FIG. 3B shows a data pad section.
Referring to FIG. 2, a gate electrode 2a is formed on a transparent insulator substrate 1, and a gate insulator layer 3 is deposited so as to cover the transparent insulator substrate 1 and the gate electrode 2a. On the gate insulator layer 3, a semiconductor layer 4 is formed so as to overlay on the gate electrode 2a. A source electrode 6a and a drain electrode 7, which are formed on different sides of the semiconductor layer 4, are respectively connected to the semiconductor layer 4 via an ohmic contact layer 5. Part of the deposited ohmic contact layer 5 between the source electrode 6a and the drain electrode 7 is removed by etching, and thus the ohmic contact layer 5 remains only between the source electrode 6a and the semiconductor layer 4 and between the drain electrode 7 and the semiconductor layer 4.
On the above structure, a passivation layer 8 is formed. On the passivation layer 8, a transparent conductive layer for becoming a pixel electrode 9 is deposited so as to be connected to the drain electrode 7 via a contact hole 11 through the passivation layer 8. A scanning signal is supplied to the gate electrode 2a via a gate line 2b, and a video signal is supplied to the source electrode 6a via a source line 6b, and thereby electric charges are written in the pixel electrode 9.
In the following, a manufacturing method of the active matrix substrate which has been shown in FIGS. 1 through 3B will be described referring to FIGS. 4A through 4E. Incidentally, only the part shown in FIG. 2 is shown in FIGS. 4A through 4E (and thus the gate pad section and the data pad section of FIGS. 3A and 3B are not shown). The following explanation will be given mainly with regard to one pixel.
First, as shown in FIG. 4A, a conductive layer of Al, Mo, Cr, etc. is deposited on the transparent insulator substrate 1 (formed of glass, for example) by sputtering to the thickness of 100xcx9c400 nm, and thereafter the first patterning step is executed so as to form the gate line 2b (unshown in FIG. 4A, shown in FIG. 1), the gate electrode 2a and a gate pad 2c (unshown in FIG. 4A, shown in FIG. 3A) (which is connected to an external display signal processor board) are formed by photo-lithography.
Subsequently, as shown in FIG. 4B, the gate insulator layer 3 (formed of silicon nitride), the semiconductor layer 4 (formed of amorphous silicon) and the ohmic contact layer 5 (formed of n+ amorphous silicon) are successively deposited by means of plasma CVD (Chemical Vapor Deposition) to the thicknesses of approximately 400 nm, 300 nm and 50 nm respectively, and thereafter the second patterning step is executed so as to pattern and form the semiconductor layer 4 and the ohmic contact layer 5 at once.
Subsequently, as shown in FIG. 4C, a layer of Mo, Cr, etc. is sputtered to the thickness of 100xcx9c200 nm so as to cover the gate insulator layer 3 and the ohmic contact layer 5, and thereafter the third patterning step is executed so as to pattern and form the source electrode 6a, the source line 6b, the drain electrode 7 and a data pad 7a (unshown in FIG. 4C, shown in FIG. 3B) (which is connected to the external display signal processor board) are formed by photo-lithography. Thereafter, unnecessary part of the ohmic contact layer 5 on the channel of the TFT is removed.
Subsequently, as shown in FIG. 4D, the passivation layer 8 (formed of an inorganic material such as silicon nitride) is deposited on the back channel of the TFT, the source electrode 6a, the source line 6b, the drain electrode 7 and the data pad 7a (unshown in FIG. 4D, shown in FIG. 3B) by means of plasma CVD to the thickness of approximately 100xcx9c200 nm, and thereafter the fourth patterning step is executed so as to form the contact hole 11 (for the connection of the drain electrode 7 and the pixel if electrode 9) and remove unnecessary part of the passivation layer 8 on the data pad 7a (unshown in FIG. 4D, shown in FIG. 3B) and remove unnecessary parts of the gate insulator layer 3 and the passivation layer 8 on the gate pad 2c (unshown in FIG. 4D, shown in FIG. 3A).
Finally, as shown in FIG. 4E, the transparent conductive layer for becoming the pixel electrode 9 is deposited by sputtering so as to be connected to the drain electrode 7 via the contact hole 11 through the passivation layer 8, and thereafter the fifth patterning step is executed so as to pattern and form the pixel electrode 9.
As explained above, the active matrix substrate which has been shown in FIG. 4A through FIG. 4E can be manufactured by only five patterning steps, therefore, the manufacturing process can be shortened considerably. A liquid crystal display device is manufactured by coupling the substrate and another substrate (which is provided with color filters and electrodes thereon) together so as to sandwich liquid crystal.
However, in the above active matrix substrate, light leaks out between the gate line 2b and the pixel electrode 9 and between the source line 6b and the pixel electrode 9 as can be seen in the plan view of FIG. 1. Therefore, the light leakage has to be shielded by providing a black matrix (or black matrixes) to the color filter substrate (that is, the aforementioned xe2x80x9canother substratexe2x80x9d). In consideration of the precision of the placement of the color filter substrate on the active matrix substrate, the light shielding area of the black matrixes has to be made considerably large, thereby the opening area ratio of the liquid crystal display device is necessitated to be small, and thereby the usage efficiency of the back light of the liquid crystal display device has to be lowered.
In order to enlarge the opening area ratio of the liquid crystal display device, a structure (CF on TFT structure) and a manufacturing method of a liquid crystal display device, in which the color filters are formed directly on the active matrix substrate, have been proposed in, for example, the first embodiment of Japanese Patent Application Laid-Open No.HEI10-39292. If we add some necessary conditions etc. which have not been mentioned in the document, the actual manufacturing method of the CF on TFT structure according to the document becomes as follows.
FIGS. 5A through 5H are cross sectional views showing the manufacturing method of the CF on TFT structure according to the above document. The TFT shown FIG. 5A is called a xe2x80x9cchannel protection TFTxe2x80x9d. Incidentally, the following explanation will be given mainly with regard to one pixel.
First, as shown in FIG. 5A, a gate electrode 2a is formed on a transparent insulator substrate 1, and a gate insulator layer 3 is deposited so as to cover the transparent insulator substrate 1 and the gate electrode 2a. On the gate insulator layer 3, a semiconductor layer 4 is formed so as to overlay on the gate electrode 2a, and a source electrode 6a and a drain electrode 7 are formed to be connected to the semiconductor layer 4. After completing such a channel protection TFT 10b, a passivation layer 8 is deposited so as to cover the above structure.
Subsequently, as shown in FIG. 5B, a pigments-dispersed photoresist for becoming the black matrix 15 is coated on the passivation layer 8 by spin coating. The number of revolutions of the spin coater is controlled so that the thickness of the black matrix 15 will become approximately 1.5 xcexcm. Thereafter the black matrix 15 is patterned by means of photo-lithography so as to overlay on the gate line 2b. By the patterning, the black matrix 15 is formed over the channel protection TFT 10b, and over a contact hole 11 (which will be formed later).
Subsequently, as shown in FIG. 5C, a red color photoresist (pigments-dispersed type) is coated on the black matrix 15 and the passivation layer 8 by spin coating to the thickness of approximately 1.2 xcexcm, and thereafter a red color filter 13a is patterned to a predetermined pattern by means of photo-lithography. In this process, by the formation of the black matrixes 15 (The plural xe2x80x9cblack matrixesxe2x80x9d means black matrixes corresponding to all the pixels of the liquid crystal display device.) before the coating of the red color photoresist, a dim residue of the red color photoresist (pigments) tends to occur on part of the passivation layer 8 where the black matrix photoresist has been removed, or a residue of the red color photoresist tends to occur due to change of the status of the surface of the passivation layer 8 by the formation and patterning of the black matrixes 15. Therefore, although not mentioned in the document (Japanese Patent Application Laid-Open No.HEI10-39292), a step for removing and cleaning a residue of the black matrix photoresist has to be executed before the coating of the red color photoresist. Concretely, the TFT substrate on which the black matrixes 15 have been formed and patterned is radiated with UV rays (of the luminous intensity of approximately 20 mW) for 60 sec, and the residue of the black matrix photoresist which has been broken down by the UV rays is removed by spin cleaning.
Subsequently, as shown in FIG. 5D-1, a green color photoresist (pigments-dispersed type) is coated by spin coating to the thickness of approximately 1.2 xcexcm, and thereafter a green color filter 13b is patterned to a predetermined pattern by means of photo-lithography. Incidentally, similarly to the case of the formation of the red color filter 13a, a residue-removing step (for removing a residue of the red color photoresist) by use of the UV rays is necessary before the formation of the green color filter 13b. 
Subsequently, as shown in FIG. 5D-2 (showing another pixel), a blue color photoresist (pigments-dispersed type) is coated by spin coating to the thickness of approximately 1.2 xcexcm, and thereafter a blue color filter 13c is patterned to a predetermined pattern by means of photo-lithography. Incidentally, similarly to the cases of the formation of the red color filter 13a and the green color filter 13b, a residue-removing step (for removing a residue of the green color photoresist) by use of the UV rays is necessary before the formation of the blue color filter 13c. 
Subsequently, as shown in FIG. 5E, an overcoat layer 14 is formed on the TFT substrate (on which the black matrixes 15, the red color filters 13a, the green color filters 13b and the blue color filters 13c have been formed) to the thickness of approximately 3 xcexcm for flattening the surface of the TFT substrate. As the overcoat layer 14, an acrylic photoresist is used. After coating the overcoat layer 14 by spin coating, part of the overcoat layer 14 corresponding to the contact hole 11 is removed and opened by means of photo-lithography. Incidentally, although not mentioned in the document (Japanese Patent Application Laid-Open No.HEI10-39292), a residue-removing step (for removing a residue of the blue color photoresist) by use of the UV rays is also necessary before the formation of the overcoat layer 14.
Subsequently, as shown in FIG. 5F, a positive novolac photoresist 17 is coated and patterned on the overcoat layer 14, and thereafter part of the black matrix 15 corresponding to the contact hole 11 is removed and opened by means of dry etching using the novolac photoresist 17 as a mask.
Subsequently, as shown in FIG. 5G, part of the passivation layer 8 corresponding to the contact hole 11 is removed and opened by means of dry etching, and thereby the opening for the contact hole 11 is completed.
Finally, as shown in FIG. 5H, a transparent conductive layer for becoming a pixel electrode 9 is sputtered on the above structure, and the pixel electrode 9 is patterned to a predetermined pattern by means of photo-lithography, thereby connection between the pixel electrode 9 and the drain electrode 7 is established, and thereby the active matrix substrate of the CF (Color Filter) on TFT structure is completed.
However, when the present inventors examined the above manufacturing method of the CF on TFT structure, some problems were found in addition to the problem which has been mentioned referring to FIG. 5C. For example, although not mentioned in the document, in the step of FIG. 5F for forming the opening for the contact hole 11, the etching of the black matrix 15 and the passivation layer 8 after hardening has to be done by means of dry etching. The black matrix 15 has been formed with the thickness of approximately 1.5 xcexcm so as to have enough light shielding effect. In order to etch the black matrix 15 using fluoride etching gas (SF6, CF4, CHF3, etc.), an etching time of approximately 200xcx9c300 sec is necessary. Further, another etching time of approximately 100xcx9c150 sec is necessary for etching the passivation layer 8 which is formed of silicon nitride etc. Therefore, an etching time of approximately 300xcx9c450 sec is necessary for forming the contact hole opening through the black matrix 15 and the passivation layer 8 by means of dry etching even when the two dry etching steps are executed at once. Therefore, the above manufacturing method of the CF on TFT structure is not suitable for mass production.
Further, the generally used novolac photoresist 17 does not have enough resistance to such a long etching time. Especially, if the etching of the black matrix 15 is not executed completely, some of the passivation layer 8 might remain in the contact hole 11 since the etching condition of the passivation layer 8 differs from that of the black matrix 15, thereby contact resistance of the contact hole 11 might be increased.
To resolve the above problems, it is also possible to preliminarily remove parts of the black matrixes 15 corresponding to the contact holes 11 at the same time as the first patterning of the black matrixes 15. Such a manufacturing method of the CF on TFT structure will be explained below referring to FIGS. 6A through 6G. Incidentally, the following explanation will be given mainly with regard to one pixel.
First, as shown in FIG. 6A, a channel protection TFT 10b is formed on a transparent insulator substrate 1, and a passivation layer 8 is deposited so as to cover the above structure.
Subsequently, as shown in FIG. 6B, a pigments-dispersed photoresist (for becoming the black matrixes 15) is coated on the passivation layer 8 by spin coating. The number of revolutions of the spin coater is controlled so that the thickness of the black matrix 15 will become approximately 1.5 xcexcm. Thereafter the black matrix 15 is patterned by means of photo-lithography so as to overlay on the gate line 2b. By the patterning, the black matrix 15 is formed over the channel protection TFT 10b, however, not formed over a contact hole 11 (which will be formed later).
Subsequently, as shown in FIG. 6C, a red color photoresist (pigments-dispersed type) is coated on the black matrix 15 and the passivation layer 8 by spin coating to the thickness of approximately 1.2 xcexcm, and thereafter a red color filter 13a is patterned to a predetermined pattern by means of photo-lithography. In this process, by the formation of the black matrixes 15 before the coating of the red color photoresist, a dim residue of the red color photoresist (pigments) tends to occur on part of the passivation layer 8 where the black matrix photoresist has been removed, or a residue of the red color photoresist tends to occur due to change of the status of the surface of the passivation layer 8 by the formation and patterning of the black matrixes 15. Therefore, a step for removing and cleaning a residue of the black matrix photoresist has to be executed before the coating of the red color photoresist. Concretely, the TFT substrate on which the black matrixes 15 have been formed and patterned is radiated with UV rays (of the luminous intensity of approximately 20 mW) for 60 sec, and the residue of the black matrix photoresist which has been broken down by the UV rays is removed by spin cleaning.
Subsequently, as shown in FIG. 6D, a green color photoresist (pigments-dispersed type) is coated by spin coating to the thickness of approximately 1.2 xcexcm, and thereafter a green color filter 13b is patterned to a predetermined pattern by means of photo-lithography. Incidentally, similarly to the case of the formation of the red color filter 13a, a residue-removing step (for removing a residue of the red color photoresist) by use of the UV rays is necessary before the formation of the green color filter 13b. Subsequently, a blue color filter 13c is also formed and patterned to a predetermined pattern in a similar manner.
Subsequently, as shown in FIG. 6E, an overcoat layer 14 is formed on the TFT substrate (on which the black matrixes 15, the red color filters 13a, the green color filters 13b and the blue color filters 13c have been formed) to the thickness of approximately 3 xcexcm for flattening the surface of the TFT substrate. As the overcoat layer 14, an acrylic photoresist is used. After coating the overcoat layer 14 by spin coating, part of the overcoat layer 14 corresponding to the contact hole 11 is removed and opened by means of photo-lithography. Incidentally, although not mentioned in the document (Japanese Patent Application Laid-Open No.HEI10-39292), a residue-removing step (for removing a residue of the blue color photoresist) by use of the UV rays is also necessary before the formation of the overcoat layer 14.
Subsequently, as shown in FIG. 6F, a positive novolac photoresist 17 is coated and patterned on the overcoat layer 14, and thereafter part of the passivation layer 8 corresponding to the contact hole 11 is removed and opened by means of dry etching using the novolac photoresist 17 as a mask.
Finally, as shown in FIG. 6G, a transparent conductive layer for becoming a pixel electrode 9 is sputtered on the above structure, and the pixel electrode 9 is patterned to a predetermined pattern by means of photo-lithography, thereby connection between the pixel electrode 9 and the drain electrode 7 is established, and thereby the active matrix substrate of the CF on TFT structure is completed.
However, in this manufacturing method of the CF on TFT structure, the parts of the black matrixes 15 corresponding to the contact holes 11 are removed when the black matrixes 15 are developed and patterned by means of photo-lithography as shown in FIG. 6B. Therefore, some residue of the black matrix photoresist remains on the parts of the passivation layer 8 corresponding to the contact holes 11. The residue of the black matrix photoresist can be removed to some extent by radiation of UV rays, however, in the subsequent formation steps of the red color filters 13a, the green color filters 13b and the blue color filters 13c, residues of the red, green and blue color photoresists occur, growing from the faint residue of the black matrix photoresist, thereby the etching of the parts of the passivation layer 8 corresponding to the contact holes 11 is made impossible.
It is of course possible to increase the UV radiation time or the luminous intensity of the UV rays in order to resolve the above problem by enhancing the effect of the UV radiation in the steps after the formation of the black matrixes 15. However, by the increase of the UV radiation time or the luminous intensity, decomposition of the black matrixes 15 progresses and thereby the resistance of the black matrix 15 is deteriorated. For example, an initial specific resistance of 1012 xcexa9xc2x7cm of the black matrix 15 is decreased to 1011 xcexa9xc2x7cm by UV radiation of 60 sec. By another 60 sec UV radiation, the specific resistance is decreased to as low as 1010 xcexa9xc2x7cm. The phenomenon continues proportionally to the UV radiation time. Such effect also occurs by the increase of the luminous intensity of the UV rays proportionally to the luminous intensity.
By the decrease of the resistance of the black matrix 15, the coupling capacitance between the black matrix 15 and source lines 6b is increased, thereby delay occurs in signals which are supplied to the drain electrode 7. According to a simulation conducted by the present inventors, the signal delay occurs when the specific resistance of the black matrix 15 is decreased to approximately 106 xcexa9xc2x7cm.
Further, a high OD (Optical Density) black matrix photoresist having strong light shielding effect has to be employed for the black matrixes 15. The black matrix photoresist is a negative photoresist which is composed of base resin (such as acrylic acid resin) and carbon dispersed in the base resin. The high OD black matrix photoresist scarcely passes light, and thus photo-polymerization of the photoresist in exposure process occurs mainly on the surface only even if the amount of exposure is increased, therefore, side walls of the black matrixes 15 tend to be dissolved by the developing solution in the development process. Therefore, the tolerances of the developing time and the developing solution concentration are necessitated to be small, thereby the result of the development process tends to vary. Concretely, the black matrixes 15 can not be patterned exactly to a predetermined pattern if the development is not enough. On the other hand, parts of the black matrixes 15 flake (strip) off from the surface of the passivation layer 8 if the development is executed excessively.
As described above, in conventional manufacturing methods of the CF (Color Filter) on TFT structure, the steps for forming the parts of the CF on TFT structure are generally executed in the order: the TFTs, the black matrixes, the color filters, the overcoat layer, the contact holes, and the pixel electrodes. By such an order (in which the color filters are formed after the formation of the black matrixes), the residues of the black matrix photoresist and the color filter photoresists tend to remain in the contact hole 11. Due to the residues, the etching of the passivation layer 8 for forming the openings for the contact holes 11 becomes impossible, and even if the contact hole 11 could successively formed, the resistance of the contact hole 11 is necessitated to become large.
If UV cleaning is executed hard in order to remove the large amount of residues, insulation coatings of carbon particles which are dispersed in the black matrix photoresist are destroyed, and thereby the resistance of the black matrix photoresist is decreased causing the signal delay.
Further, in the conventional manufacturing methods, side walls of the black matrixes 15 are fully exposed to the developing agent in the development process, and thus pattern flake-off of the black matrixes 15 tends to occur.
It is therefore the primary object of the present invention to provide a liquid crystal display device of on-array color filter structure (i.e. the CF (Color Filter) on TFT structure etc. in which switching elements (such as TFTs) and color filters are formed on a common substrate so as to have a large opening area ratio (a large usage efficiency of the back light)), in which the etching of the passivation layer 8 for forming the contact hole openings can be executed easily and reliably, the contact resistance of the contact hole 11 can be decreased, signal delay can be avoided by securing a large resistance of the black matrix 15, the pattern flake-off of the black matrixes 15 can be eliminated, and the light leakage can be eliminated correctly.
Another object of the present invention is to provide a manufacturing method of a liquid crystal display device, by which the liquid crystal display device having the above characteristics can be manufactured efficiently.
In accordance with a first aspect of the present invention, there is provided a liquid crystal display device comprising a transparent insulator substrate, switching elements, a passivation layer, color filters of prescribed colors, black matrixes, an overcoat layer, pixel electrodes, lead electrodes, and contact holes. The switching elements are formed on the transparent insulator substrate. The passivation layer is formed for passivating the switching elements. The color filters of prescribed colors are formed on the passivation layer so that no color filter will be formed in areas around contact holes. The black matrixes are formed as shields for preventing light leakage. The black matrixes are formed on the passivation layer after the formation of the color filters so as to cover at least the switching elements, and so that no black matrix will be formed in areas around the contact holes. The overcoat layer is formed on the color filters and the black matrixes. The pixel electrodes are formed on the overcoat layer. The lead electrode is provided to each of the switching elements for being connected to a corresponding one of the pixel electrodes. The contact holes are formed through the overcoat layer and the passivation layer for establishing connection between the pixel electrodes and lead electrodes of the switching elements.
In accordance with a second aspect of the present invention, in the first aspect, the black matrixes are formed so that the edge of the black matrix touching the edge of the color filter will be superposed on the edge of the color filter.
In accordance with a third aspect of the present invention, in the first aspect, the color filters are formed of pigments-dispersed photoresists.
In accordance with a fourth aspect of the present invention, in the third aspect, the pigments-dispersed photoresists which are used for forming the color filters are acrylic pigments-dispersed photoresists.
In accordance with a fifth aspect of the present invention, in the first aspect, the black matrixes are formed of a pigments-dispersed photoresist.
In accordance with a sixth aspect of the present invention, in the fifth aspect, the pigments-dispersed photoresist which is used for forming the black matrixes is an acrylic pigments-dispersed photoresist.
In accordance with a seventh aspect of the present invention, in the fifth aspect, carbon particles are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with an eighth aspect of the present invention, in the fifth aspect, carbon particles provided with insulation coatings are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with a ninth aspect of the present invention, in the fifth aspect, titanium oxide particles are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with a tenth aspect of the present invention, in the first aspect, the overcoat layer is formed of a transparent photoresist.
In accordance with an eleventh aspect of the present invention, in the tenth aspect, the transparent photoresist is a transparent acrylic photoresist.
In accordance with a twelfth aspect of the present invention, in the first aspect, the switching element is a TFT (Thin-Film Transistor), and the lead electrode is the drain electrode of the TFT.
In accordance with a thirteenth aspect of the present invention, in the first aspect, the black matrixes are formed so as to be connected to each other across pixels which are arranged in a particular direction.
In accordance with a fourteenth aspect of the present invention, there is provided a manufacturing method of a liquid crystal display device, comprising a switching element formation step, a passivation layer formation step, a color filter formation step, a black matrix formation step, an overcoat layer formation step, a contact hole opening formation step, and a pixel electrode formation step. In the switching element formation step, switching elements, each of which has a lead electrode for being connected to a corresponding pixel electrode, are formed on a transparent insulator substrate. In the passivation layer formation step, a passivation layer for passivating the switching elements is formed on the substrate on which the switching elements have been formed. In the color filter formation step, color filters of prescribed colors are formed on the passivation layer to predetermined patterns so that no color filter will be formed in areas around contact holes. In the black matrix formation step, black matrixes, as shields for preventing light leakage, are formed on the substrate on which the color filters have been formed. The black matrixes are formed so as to cover at least the switching elements, and so that no black matrix will be formed in areas around the contact holes. In the overcoat layer formation step, an overcoat layer is formed on the substrate on which the color filters and the black matrixes have been formed. The overcoat layer is formed to a pattern having openings for the contact holes. In the contact hole opening formation step, openings for the contact holes are formed in the passivation layer by etching corresponding parts of the passivation layer. In the pixel electrode formation step, the pixel electrodes are formed on the overcoat layer by depositing a transparent conductive layer on the patterned overcoat layer and on parts of the lead electrodes which have been exposed in the contact hole openings and thereafter patterning the transparent conductive layer to a predetermined pattern.
In accordance with a fifteenth aspect of the present invention, in the black matrix formation step of the fourteenth aspect, the black matrixes are formed so that the edge of the black matrix touching the edge of the color filter will be superposed on the edge of the color filter.
In accordance with a sixteenth aspect of the present invention, in the contact hole opening formation step of the fourteenth aspect, the etching of the passivation layer is executed using a photoresist patterned on the overcoat layer as a mask.
In accordance with a seventeenth aspect of the present invention, in the contact hole opening formation step of the fourteenth aspect, the etching of the passivation layer is executed using the patterned and hardened overcoat layer as a mask.
In accordance with an eighteenth aspect of the present invention, in the seventeenth aspect, the etching of the passivation layer is executed by means of plasma etching using one or more selected from SF6, He and O2 as etching gasses.
In accordance with a nineteenth aspect of the present invention, in the fourteenth aspect, the color filter formation step for each prescribed color includes a photoresist coating step, a prebaking step, an exposure step, a development step, and a baking step.
In accordance with a twentieth aspect of the present invention, in the color filter formation step of the fourteenth aspect, the color filters are formed of pigments-dispersed photoresists.
In accordance with a twenty-first aspect of the present invention, in the twentieth aspect, the pigments-dispersed photoresists which are used for forming the color filters are acrylic pigments-dispersed photoresists.
In accordance with a twenty-second aspect of the present invention, in the fourteenth aspect, the black matrix formation step includes a photoresist coating step, a prebaking step, an exposure step, a development step, and a baking step.
In accordance with a twenty-third aspect of the present invention, in the twenty-second aspect, the exposure step is executed in a nitrogen gas atmosphere.
In accordance with a twenty-fourth aspect of the present invention, in the fourteenth aspect, the black matrix formation step includes a photoresist coating step, a prebaking step, an exposure step, a PEB (Post Exposure Bake) step, a development step, and a baking step.
In accordance with a twenty-fifth aspect of the present invention, in the twenty-fourth aspect, the exposure step is executed in a nitrogen gas atmosphere.
In accordance with a twenty-sixth aspect of the present invention, in the fourteenth aspect, the black matrix formation step includes a photoresist coating step, a first prebaking step, an oxygen passivation layer coating step, a second prebaking step, an exposure step, a PEB (Post Exposure Bake) step, an oxygen passivation layer removing step, a development step, and a baking step.
In accordance with a twenty-seventh aspect of the present invention, in the twenty-sixth aspect, the exposure step is executed in a nitrogen gas atmosphere.
In accordance with a twenty-eighth aspect of the present invention, in the twenty-sixth aspect, the oxygen passivation layer is formed of polyvinyl alcohol resin.
In accordance with a twenty-ninth aspect of the present invention, in the black matrix formation step of the fourteenth aspect, the black matrixes are formed of a pigments-dispersed photoresist.
In accordance with a thirtieth aspect of the present invention, in the twenty-ninth aspect, the pigments-dispersed photoresist which is used for forming the black matrixes is an acrylic pigments-dispersed photoresist.
In accordance with a thirty-first aspect of the present invention, in the twenty-ninth aspect, carbon particles are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with a thirty-second aspect of the present invention, in the twenty-ninth aspect, carbon particles provided with insulation coatings are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with a thirty-third aspect of the present invention, in the twenty-ninth aspect, titanium oxide particles are employed as the pigments for the pigments-dispersed photoresist for the black matrixes.
In accordance with a thirty-fourth aspect of the present invention, in the twenty-ninth aspect, an initialization agent having high sensitivity for the xe2x80x9cgxe2x80x9d, xe2x80x9chxe2x80x9d and xe2x80x9cixe2x80x9d lines is added to the pigments-dispersed photoresist for the black matrixes.
In accordance with a thirty-fifth aspect of the present invention, in the black matrix formation step of the fourteenth aspect, the black matrixes are formed so as to be connected to each other across pixels which are arranged in a particular direction.
In accordance with a thirty-sixth aspect of the present invention, in the fourteenth aspect, the manufacturing method further comprises an HMDS (HexaMethylDiSilane) exposure step in which the substrate is exposed to an HMDS gas atmosphere before the color filter formation step.
In accordance with a thirty-seventh aspect of the present invention, in the fourteenth aspect, the manufacturing method further comprises an HMDS (HexaMethylDiSilane) exposure step in which the substrate is exposed to an HMDS gas atmosphere before the black matrix formation step.
In accordance with a thirty-eighth aspect of the present invention, in the overcoat layer formation step of the fourteenth aspect, the overcoat layer is formed of a transparent photoresist.
In accordance with a thirty-ninth aspect of the present invention, in the thirty-eighth aspect, the transparent photoresist is a transparent acrylic photoresist.
In accordance with a fortieth aspect of the present invention, in the fourteenth aspect, the switching element which is formed in the switching element formation step is a TFT (Thin-Film Transistor), and the lead electrode is the drain electrode of the TFT.